When flying through the clouds, the planes force the air nearby to expand and cool rapidly. This causes the water droplets within the cloud to freeze – first into ice and then snow – as the precipitation falls toward the ground.

Afterward, the clouds are often left with odd-shaped gaps, which make it look as if someone used a giant hole-punch on the cloud.

The researchers think this phenomenon, which some consider inadvertent cloud seeding, occurs at a number of other airports as well, especially those located in mid- to high-latitude areas during colder months.

One element that seems to be a key variable is whether there are cloud layers in the vicinity which contain water droplets at temperatures far below freezing, which is quite common.

The study team says more research is needed to determine whether the precipitation produced by this effect is significant.